rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 ticks this GP) idle=ff14/1/0x4000000000000000 softirq=554965/554992 fqs=3
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P28895/1:b..l P5197/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=304601, q=341 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 28890 Comm: syz.4.6202 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:_find_first_zero_bit+0xc/0xb0 lib/find_bit.c:148
Code: 81 fd e9 7c ff ff ff 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 <53> 48 85 f6 74 46 48 89 f3 49 89 fe 49 bc 00 00 00 00 00 fc ff df
RSP: 0018:ffffc9000605fc20 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff888035e7c8d0 RCX: 0000000080000001
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff888035e7c8d0
RBP: 0000000080000000 R08: 1ffff11006bcf7c9 R09: 0000000000000000
R10: ffff888035e7bf94 R11: fffff52000c0bf78 R12: 1ffffffff1c363d3
R13: 0000000080000000 R14: 0000000000000002 R15: ffff888035e7bd40
FS: 00007fe55b5c86c0(0000) GS:ffff88812545d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000192000 CR3: 000000004b680000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
find_first_zero_bit include/linux/find.h:393 [inline]
__mm_get_cid kernel/sched/sched.h:3835 [inline]
mm_get_cid kernel/sched/sched.h:3850 [inline]
sched_mm_cid_fork+0x5d5/0x1120 kernel/sched/core.c:10679
bprm_execve+0xda1/0x1460 fs/exec.c:1771
do_execveat_common+0x50d/0x690 fs/exec.c:1846
__do_sys_execveat fs/exec.c:1941 [inline]
__se_sys_execveat fs/exec.c:1934 [inline]
__x64_sys_execveat+0xc7/0xf0 fs/exec.c:1934
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe55a79c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe55b5c8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 00007fe55aa15fa0 RCX: 00007fe55a79c799
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007fe55a832c99 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe55aa16038 R14: 00007fe55aa15fa0 R15: 00007fe55ab3fa48
task:udevd state:R running task stack:22976 pid:5197 tgid:5197 ppid:1 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238
irqentry_exit+0x599/0x620 kernel/entry/common.c:239
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:100 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline]
RIP: 0010:unwind_next_frame+0x539/0x23c0 arch/x86/kernel/unwind_orc.c:510
Code: 0f b6 04 08 84 c0 75 27 49 63 07 4c 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 49 8d 47 fc 48 0f 47 d8 4d 0f 46 ef 48 39 dd 76 a2 76 fd ff ff 44 89 f9 80 e1 07 80 c1 03 38 c1 7c cc 4c 89 ff 48
RSP: 0018:ffffc90002f279d8 EFLAGS: 00000202
RAX: ffffffff902d18e8 RBX: ffffffff902d18e8 RCX: ffffffff902d18f0
RDX: ffffffff902d18e8 RSI: ffffffff90aabec2 RDI: ffffffff8c27c8a0
RBP: ffffffff902d18ec R08: 000000000000000c R09: ffffffff8e75e5e0
R10: ffffc90002f27af8 R11: ffffffff81b0c390 R12: ffffffff81b0c328
R13: ffffffff902d18e8 R14: ffffc90002f27aa8 R15: ffffffff902d18ec
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2685 [inline]
slab_free mm/slub.c:6165 [inline]
kmem_cache_free+0x187/0x630 mm/slub.c:6295
free_filename fs/namei.c:147 [inline]
putname fs/namei.c:306 [inline]
class_filename_destructor include/linux/fs.h:2539 [inline]
__do_sys_unlink fs/namei.c:5576 [inline]
__se_sys_unlink+0xc2/0x140 fs/namei.c:5572
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0054115937
RSP: 002b:00007ffe1fbc2138 EFLAGS: 00000202 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000bb8 RCX: 00007f0054115937
RDX: 0000000000000000 RSI: 0000000063101b80 RDI: 000055dbf365d02e
RBP: 0000000000000000 R08: 000000006310dcad R09: 3fffffffffffffff
R10: 4000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 000055dbf3678100 R14: 0000000000000001 R15: 0000000000000000
task:syz.6.6203 state:R running task stack:27272 pid:28895 tgid:28892 ppid:23005 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238
irqentry_exit+0x599/0x620 kernel/entry/common.c:239
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x2d7/0x3d0 kernel/locking/lockdep.c:5893
Code: b7 7a 11 00 00 00 00 eb b5 e8 05 04 0d 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 85 71 7a 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 32 4c 73
RSP: 0018:ffffc900063bf560 EFLAGS: 00000286
RAX: 207bacfac1e47600 RBX: 0000000000000202 RCX: 0000000000000046
RDX: 0000000000000001 RSI: ffffffff8e1699dc RDI: ffffffff8c27c900
RBP: ffff8880656f2a00 R08: ffffc900063bfa90 R09: 0000000000000000
R10: ffffc900063bf6b8 R11: fffff52000c77ed9 R12: 0000000000000001
R13: 0000000000000001 R14: ffffffff8e75e5e0 R15: ffff8880656f1e80
rcu_lock_release include/linux/rcupdate.h:322 [inline]
rcu_read_unlock include/linux/rcupdate.h:881 [inline]
class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0x1aaa/0x23c0 arch/x86/kernel/unwind_orc.c:695
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4538 [inline]
kmem_cache_alloc_bulk_noprof+0x570/0x7e0 mm/slub.c:7288
__io_alloc_req_refill+0xb4/0x360 io_uring/io_uring.c:965
io_alloc_req io_uring/io_uring.h:508 [inline]
io_submit_sqes+0x1011/0x2400 io_uring/io_uring.c:2032
__do_sys_io_uring_enter io_uring/io_uring.c:2604 [inline]
__se_sys_io_uring_enter+0x2cc/0x18c0 io_uring/io_uring.c:2539
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0d73b9c799
RSP: 002b:00007f0d71db4028 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007f0d73e16180 RCX: 00007f0d73b9c799
RDX: 00000000ffffdffd RSI: 0000000000004fee RDI: 0000000000000008
RBP: 00007f0d73c32c99 R08: 0000000000000000 R09: fffffffffffffd95
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0d73e16218 R14: 00007f0d73e16180 R15: 00007f0d73f3fa48
rcu: rcu_preempt kthread starved for 10489 jiffies! g304601 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27744 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7008
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: 5e 6c 02 c3 cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d e3 a2 1a 00 fb f4 fc e9 02 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 00000246
RAX: 0000000002c909af RBX: ffffffff819a913a RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8def8bf9 RDI: ffffffff8c27c900
RBP: ffffc90000197f10 R08: ffff8880b873399b R09: 1ffff110170e6733
R10: dffffc0000000000 R11: ffffed10170e6734 R12: 0000000000000001
R13: 1ffff11003ad9000 R14: 0000000000000001 R15: 1ffff11003ad9000
FS: 0000000000000000(0000) GS:ffff88812555d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000404000 CR3: 00000000523a2000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/kernel/process.c:766 [inline]
default_idle+0x9/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x36a/0x5f0 kernel/sched/idle.c:352
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x147